Mechanical parts collect dirt, abrasion residue, used grease, and other debris during normal operation. Rollers in the printing industry are used to lick ink or other chemicals from reservoirs and spread these chemicals across substrates in a well-defined pattern found on other rollers. Print rollers progressively collect dirt, loose particles, and even dry ink. Five different technologies are know in the industry: manual parts washing, automatic parts washing, spray-under-immersion cleaning, soaked parts washing and abrasive blast cleaning using a variety of different media. Washing print rollers can be done manually using a sponge, a brush, or a towel or facilitated using automated devices. Some devices operate onsite without the need for the removal of the print roller, while others operate offsite once the print roller is removed and transported to a print roller cleaner. The current disclosure relates to automatic parts washers using immersion cleaning with or without spray-under-immersion cleaning and soak washing under immersion.
A parts washer is an apparatus that cleans parts, either individually or in groups, including but not limited to cleaning of machinery and machine parts or print rollers. Immersion cleaners are a subgroup of parts washers where mechanical parts, such as print rollers, are immersed in a cleaning solution during cleaning operations. The core technology associated with immersion cleaners is not unlike the technology associated with the immersion cleaning of automobile parts at repair shops. Some parts washers use an aqueous cleaning solution to dissolve and remove grease, carbon, resins, tar, inks, and other debris. These parts washers use water, soap, and/or detergents, either common or proprietary. Other more aggressive parts washers use hydrocarbon-based solvents or other solvents to degrease and wash parts. Cleaning solutions may in some cases be abrasive, solvent based, or corrosive and require confinement and ultimately recycling. Even if water-based solutions are used in the immersion process, the washed residue can be abrasive, solvent based, or corrosive and require confinement, filtration, and processing.
Print rollers are generally heavy cylindrical parts with somewhat delicate printing surfaces having two supporting ends also of cylindrical shape. Rollers of different lengths and radii must be used in the printing industry, often in tandem on a single printing press. Print roller washers must accommodate differently sized rollers with different lengths, radii, and weights. Cleaning requires relative movement of the cleaning solution and the surface of the printing roller to help with the dissolution of dirt particles in the cleaning solution. The most efficient way to move the roller in the cleaning solution is to allow the roller to roll creating a maximum velocity of cleaning solution at the surface. Other relative movements are difficult because of the inertia of the roller in the fluid. To rotate the print rollers, a driving means is required; in the prior art, mechanically driven means are used, either via chains, belts, connected to a motor. Unlike the cleaning solution that can easily be regenerated, the driving means and motor must periodically be cleaned. What is needed is a driving means that does not require any periodic maintenance or cleaning. Another common problem of the prior art is the incapacity to clean both the entire printing surface and the ends, the prior art systematically holds the print roller either on wheels located at a position along the printing surface or by the ends. In both cases, lines or surfaces cannot be effectively cleaned. What is needed is a support system, that reduces cleaning interferences by allowing the cleaning solution to reach the entire external surface of the print roller during washing operations.
One model of immersion print roller washer from the prior art, described in U.S. Pat. No. 5,291,827, disclose a large, rectangular reservoir where the print roller is immersed in a cleaning solution. The sides of the reservoir are equipped with a lowering and holding mechanism. A roller chain driven drive mechanism is attached to support rollers and rotate the print rollers to be washed. Obvious disadvantages of this system includes the incapacity to accommodate narrow print rollers and the need to use a drive mechanism partly immersed in the cleaning solution, that pulls cleaning solution out of the reservoir and ultimately degrades a non immersed motor.
A more recent model from the prior art, described in U.S. Pat. No. 5,636,571, is equipped with a large, open reservoir to accommodate a plurality of rollers attached to the top surface of the reservoir. Rail systems can be adjusted to accommodate narrow print rollers and the drive mechanism is external to the reservoir and supports part of the print rollers held outside of the cleaning solution. The obvious disadvantages of this system includes the incapacity to clean one of the critical portion of the print roller: the supporting ends. This device also requires a top cover to prevent splashing or evaporation of fumes during the washing process.
In another type of print roller immersion washer described in U.S. Pat. No. 5,490,460, print rollers are fully immersed in cleaning solution in an reservoir but are placed on rotating pegs in contact with the delicate printing surface of the print roller while the driving mechanism rotates the roller in the cleaning solution. A single belt-based drive mechanism is shown and connected with a motor located outside of the reservoir. Obvious disadvantages of this device is the need for sets of wheels and the incapacity to clean a print roller without resorting to a full support on the printing surface over wheels near the extremity of the print roller.
What is needed is a immersion cleaner for print rollers capable of cleaning the entire print roller without damaging the printing surface of the print rollers. What is also needed is an immersion cleaner capable of rotating print rollers without the need for a roller chain or a strap in the interface between the cleaning solution and the dry portion of the printing cylinder washer.